LONDON -- The Duchess of Cambridge is trying to shatter the stigma attached to mental health issues as she guest edits an edition of the Huffington Post.

The former Kate Middleton said Wednesday that she and Prince William wouldn't hesitate to seek help if they thought their children, George and Charlotte, needed it. Her comments came as the news website marked the start of a campaign called Young Minds Matter, which raises awareness around mental health in children.

The duchess --the patron of several charities that deal with the issue -- spent the day working with Huffington Post staff and mental health campaigners from a temporary newsroom set up in her Kensington Palace home. She wrote that she's heard "heart-breaking stories about lives that had been torn apart."

She called for change, writing that "with mental health problems still being such a taboo, many adults are often too afraid to ask for help for the children in their care."

U.S. first lady Michelle Obama also wrote an article for the site, praising Kate for shining "a bright light on mental health, particularly children's mental health, and on the tens of millions of people who suffer in silence."